(Trifluoromethyl)pyridine compounds for use in making herbicides are customarily prepared by the fluorination of (trichloromethyl)pyridine compounds as described, for example, in copending application Ser. No. 520,399 filed Aug. 4, 1983. Such processes generally require the use of an excess of fluorinating agent, e.g. hydrogen fluoride, and even when employing a reflux condenser, the vent gases from the fluorination reactor, usually a mixture of hydrogen fluoride and hydrogen chloride, must be collected and disposed of in an environmentally acceptable way, such as, for example, by contacting with aqueous NaOH. That method produces an aqueous waste product containing substantial quantities of fluoride.